Ultrasonic liquid level sensing systems

ABSTRACT

Embodiments of the present invention provide an ultrasonic probe having an increased number (e.g., twelve) of ultrasonic sensors for measuring the level of liquid within a sealed container. The ultrasonic probe includes a neck tube that enables the ultrasonic probe to be used with existing, standardized container fittings despite having an enlarged barrel to accommodate the increased number of ultrasonic sensors. Embodiments of the present invention also provide a system and method in which ultrasonic sensors within an ultrasonic probe are activated one at a time to reduce crosstalk between the ultrasonic sensors and their wiring.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/823,625, filed May 15, 2013, which is hereby incorporated byreference as if fully set forth.

BACKGROUND OF THE INVENTION

Semiconductor manufacturing processes involve the use of chemicalreagents that must meet strict purity requirements. These liquidchemical reagents are typically contained in sealed containers (e.g.,ampoules) to protect against contamination of the chemical reagents andto prevent leakage. The chemical reagents typically require metalcontainers and container fittings that use metal-on-metal seals to avoidcorrosion, contamination, and leakage under elevated pressures. Whenusing a chemical reagent stored in such a container, it is oftennecessary to be able to determine the amount of chemical reagent left inthe container without exposing the chemical reagent to the environmentor exposing an operator to the chemical reagent.

Ultrasonic probes are commonly used in the semiconductor industry tomeasure the level of chemical reagent within a sealed container. Atypical design includes multiple ultrasonic sensors positioned in aseries along the length of a conduit within the probe, such as thesensors and configuration disclosed in U.S. Pat. No. 5,663,503 to Dam etal. A signal processing device (e.g., a controller, meter, personalcomputer, etc.) transmits electronic signals to the ultrasonic sensors,which in turn generate bursts of sound waves that pass through theconduit and echo back to the sensors. Each sensor converts the echoedwaves it receives into electronic signals that are transmitted back tothe signal processing device. The signal processing device theninterprets the electronic signals to determine the intensity of theechoed waves as well as the time that elapsed between emission and thearrival of the echoed waves. For each sensor positioned along aparticular portion of the conduit, the speed with which the ultrasonicwaves travel through the conduit and the intensity of the echoedultrasonic wave will differ depending on whether that portion of theconduit contains chemical reagent or gas or vapor (i.e., sound travelsfaster through a liquid medium as compared to gas or vapor). In thismanner, the signal processing device can determine the level of thechemical reagent along the length of the conduit and therefore theamount of chemical reagent within the container.

Generally, a greater number of ultrasonic sensors disposed within theultrasonic probe translates into increased accuracy in measuringchemical reagent levels. However, a larger probe is typically requiredto accommodate the increased number of ultrasonic sensors and theirwiring. Given the exacting nature of semiconductor manufacturingprocesses and environments, the dimensions of sealed containers,container fittings, seals, and related hardware are largelystandardized, which limits the extent to which the ultrasonic probes canbe adapted to include a greater number of ultrasonic sensors (e.g.,greater than four) without requiring a change to larger fittings and/ornon-standardized components.

Accordingly, there is a need in the art for an ultrasonic probe havingan increased number of ultrasonic sensors that can be used withexisting, standardized container fittings.

SUMMARY OF THE INVENTION

According to one embodiment the present invention, an ultrasonic probefor use with a container is disclosed. The ultrasonic probe comprises abarrel having an outer diameter and a conduit disposed within thebarrel, the conduit having an upper opening and a lower opening. A necktube is coupled to the barrel and a portion of a fitting assembly, theneck tube comprising a shoulder portion, a lower opening defined by theshoulder portion, a side wall, and a first outer diameter defined by thesidewall, the first outer diameter of the neck tube being less than theouter diameter of the barrel. An internal volume is disposed within thebarrel, the internal volume being isolated from the conduit. A pluralityof ultrasonic sensors is disposed within the internal volume, with eachultrasonic sensor of the plurality of ultrasonic sensors having a wirethat extends from the internal volume through the neck tube.

In addition, several specific aspects of the systems and methods of thepresent invention are outlined below.

Aspect 1. An ultrasonic probe for use with a container, the ultrasonicprobe comprising:

a barrel having an outer diameter;

a conduit disposed within the barrel;

a neck tube coupled to the barrel and a portion of a fitting assembly,the neck tube comprising a shoulder portion, a lower opening defined bythe shoulder portion, a side wall, and a first outer diameter defined bythe sidewall, the first outer diameter of the neck tube being less thanthe outer diameter of the barrel;

an internal volume disposed within the barrel, the internal volume beingisolated from the conduit; and

a plurality of ultrasonic sensors disposed within the internal volume,each ultrasonic sensor of the plurality of ultrasonic sensors having awire that extends from the internal volume through the neck tube.

Aspect 2. The ultrasonic probe of Aspect 1, wherein the portion of thefitting assembly comprises a sealing surface having an inner edge, theinner edge being located at least 2.0 mm from the sidewall of the necktube.

Aspect 3. The ultrasonic probe of Aspects 1 or 2, wherein the outerdiameter of the barrel is at least five-sixteenths of an inch (7.9 mm).

Aspect 4. The ultrasonic probe of any of Aspects 1 through 3, whereinthe ratio of the first outer diameter of the neck tube to the outerdiameter of the barrel is less than or equal to 0.95.

Aspect 5. The ultrasonic probe of any of Aspects 1 through 3, whereinthe ratio of the first outer diameter of the neck tube to the outerdiameter of the barrel is greater than or equal to 0.3 and less than orequal to 0.95.

Aspect 6. The ultrasonic probe of any of Aspects 1 through 5, whereinthe first outer diameter of the neck tube is no greater than 21.0 mm.

Aspect 7. The ultrasonic probe of any of Aspects 1 through 6, whereinthe barrel comprises:

a collar having an upper opening, a lower opening, a sidewall, a sideopening disposed in the sidewall, and an outer diameter defined by thesidewall;

an outer tube comprising an upper opening, a lower opening, a sidewall,and an outer diameter defined by the sidewall; and

an inner tube comprising an upper opening, a lower opening, and asidewall, the upper opening of the inner tube being aligned with theside opening of the collar;

wherein the inner tube defines the conduit, the internal volume islocated between the sidewall of the inner tube and the sidewall of theouter tube, the side opening of the collar is aligned with the upperopening of the inner tube, and the collar is positioned between the necktube and the outer tube.

Aspect 8. The ultrasonic probe of any of Aspects 1 through 7, whereinthe barrel comprises:

a collar having an upper opening, a lower opening, a sidewall, a sideopening disposed in the sidewall, and an outer diameter defined by thesidewall, the upper opening of the collar being coupled to the loweropening of the neck tube;

an outer tube comprising an upper opening, a lower opening, a sidewall,and an outer diameter defined by the sidewall, the upper opening of theouter tube being coupled to the lower opening of the collar; and

an inner tube coupled to the outer tube and the collar, the inner tubecomprising an upper opening, a lower opening, and a sidewall, the upperopening of the inner tube being aligned with the side opening of thecollar, the lower opening of the inner tube being aligned with the loweropening of the outer tube;

wherein the inner tube defines the conduit and the internal volume islocated between the sidewall of the inner tube and the sidewall of theouter tube.

Aspect 9. The ultrasonic probe of any of Aspects 1 through 8, whereinthe lower opening defined by the shoulder portion of the neck tube has asecond outer diameter, the second outer diameter being greater than thefirst outer diameter of the neck tube.

Aspect 10. The ultrasonic probe of Aspect 9, wherein the second outerdiameter is substantially equal to the outer diameter of the outer tubeand the outer diameter of the collar.

Aspect 11. The ultrasonic probe of any of Aspects 1 through 6, whereinthe barrel comprises:

an outer tube comprising an upper opening, a lower opening, a sidewall,and a side opening disposed in the sidewall; and

an inner tube coupled to the outer tube, the inner tube comprising anupper opening, a lower opening, and a sidewall, the upper opening of theinner tube being aligned with the side opening of the outer tube, thelower opening of the inner tube being aligned with the lower opening ofthe outer tube, wherein the inner tube defines the conduit, wherein theinternal volume is located between the sidewall of the inner tube andthe sidewall of the outer tube.

Aspect 12. The ultrasonic probe of Aspect 11, wherein the shoulderportion of the neck tube comprises:

a shoulder tube coupled to the sidewall of the neck tube, the shouldertube being coupled to the outer tube, the shoulder tube having an outerdiameter that is greater than the first outer diameter.

Aspect 13. The ultrasonic probe of any of Aspects 1 through 12, whereinthe portion of the fitting assembly comprises:

a first seal fitting member coupled to a portion of the neck tube, thefirst seal fitting member comprising a first threaded region and aprotruding sealing surface, the protruding sealing surface of the firstseal fitting member extending around the neck tube, the protrudingsealing surface of the first seal fitting member being separated fromthe sidewall of the neck tube by a first distance.

Aspect 14. The ultrasonic probe of Aspect 13, further comprising:

a second seal fitting member, the second seal fitting member comprisinga second threaded region, wherein the second threaded region is adaptedto engage the first threaded region; and

a gasket having a through hole through which the neck tube is disposed,the gasket being adapted to be disposed between the protruding sealingsurface of the first seal fitting member and a protruding sealingsurface of the container.

Aspect 15. The ultrasonic probe of Aspects 13 or 14, wherein the firstdistance is at least 2.0 mm.

Aspect 16. The ultrasonic probe of any of Aspects 13 through 15, whereinthe first seal fitting member comprises a three-quarter-inch (19.1 mm)face seal fitting.

Aspect 17. A system comprising:

a container for holding a liquid, the container comprising:

a body having an upper portion and an internal volume; and

a stem disposed in a hole in the upper portion of the body, the stemhaving an inner diameter, a sidewall, a lip, and a protruding sealingsurface; and

an ultrasonic probe for measuring levels of liquid in the internalvolume of the container, the ultrasonic probe comprising:

a barrel having an outer diameter that is less than the inner diameterof the stem, the barrel having a conduit disposed within the barrel, theconduit being in flow communication with the internal volume of the bodyof the container;

a neck tube coupled to the barrel and a portion of a fitting assembly,the neck tube comprising a shoulder portion, a lower opening defined bythe shoulder portion, a side wall, and a first outer diameter defined bythe sidewall, the first outer diameter of the neck tube being less thanthe outer diameter of the barrel, wherein a portion of the neck tube isdisposed within the stem;

an internal volume disposed within the barrel, the internal volume ofthe barrel being isolated from the conduit and the internal volume ofthe body of the container; and

a plurality of ultrasonic sensors disposed within the internal volume ofthe barrel, each ultrasonic sensor of the plurality of ultrasonicsensors having a wire that extends from the internal volume of thebarrel and through the neck tube, each ultrasonic sensor of theplurality of ultrasonic sensors being positioned and oriented to emitsound waves into at least a portion of the conduit.

Aspect 18. The system of Aspect 17, wherein the portion of the fittingassembly comprises a sealing surface having an inner edge, the inneredge being located at least 2.0 mm from the sidewall of the neck tube.

Aspect 19. The system of Aspects 17 or 18, wherein the ratio of thefirst outer diameter of the neck tube to the outer diameter of thebarrel is less than or equal to 0.95.

Aspect 20. The system of any of Aspects 17 through 19, wherein thebarrel further comprises:

a collar having an upper opening, a lower opening, a sidewall, a sideopening disposed in the sidewall, and an outer diameter defined by thesidewall, the upper opening of the collar being coupled to the necktube;

an outer tube comprising an upper opening, a lower opening, a sidewall,and an outer diameter defined by the sidewall, the upper opening of theouter tube being coupled to the lower opening of the collar; and

an inner tube coupled to the outer tube and the collar, the inner tubecomprising an upper opening, a lower opening, and a sidewall, the upperopening of the inner tube being aligned with the side opening of thecollar, the lower opening of the inner tube being aligned with the loweropening of the outer tube, wherein the inner tube defines the conduit,wherein the internal volume is located between the sidewall of the innertube and the sidewall of the outer tube.

Aspect 21. The system of any of Aspects 17 through 20, wherein the loweropening defined by the shoulder portion of the neck tube is locatedbelow a lower-most portion of the stem when the ultrasonic probe isfully installed on the container.

Aspect 22. The system of any of Aspects 17 through 21, wherein the loweropening defined by the shoulder portion of the neck tube has a secondouter diameter, the second outer diameter being greater than the firstouter diameter of the neck tube.

Aspect 23. The system of any of Aspects 20 through 22, wherein thesecond outer diameter is substantially equal to the outer diameter ofthe outer tube and the outer diameter of the collar.

Aspect 24. The system of any of Aspects 17 through 19, wherein thebarrel comprises:

an outer tube comprising an upper opening, a lower opening, a sidewall,and a side opening disposed in the sidewall; and

an inner tube coupled to the outer tube, the inner tube comprising anupper opening, a lower opening, and a sidewall, the upper opening of theinner tube being aligned with the side opening of the outer tube, thelower opening of the inner tube being aligned with the lower opening ofthe outer tube, wherein the inner tube defines the conduit, wherein theinternal volume of the barrel is located between the sidewall of theinner tube and the sidewall of the outer tube.

Aspect 25. The system of Aspect 24, wherein the shoulder portion of theneck tube comprises:

a shoulder tube coupled to the sidewall of the neck tube, the shoulderbeing coupled to the outer tube, the shoulder tube having an outerdiameter that is greater than the first outer diameter.

Aspect 26. The system of Aspect 25, wherein the lower opening of theshoulder tube is located below a lower-most portion of the stem when theultrasonic probe is fully installed on the container.

Aspect 27. The system of any of Aspects 17 through 26, wherein theportion of the fitting assembly comprises:

a first seal fitting member coupled to a portion of the neck tube, thefirst seal fitting member comprising a first threaded region and aprotruding sealing surface extending around the neck tube, theprotruding sealing surface of the first seal fitting member beingseparated from the sidewall of the neck tube by at least 2.0 mm.

Aspect 28. The system of Aspect 27, further comprising:

a second seal fitting member, the second seal fitting member comprisinga second threaded region, wherein the second threaded region engages thefirst threaded region and the lip of the stem of the container engages aportion of the second seal fitting member; and

a gasket disposed between the protruding sealing surface of the firstseal fitting member and the protruding sealing surface of the stem ofthe container, the gasket having a through hole through which the necktube is disposed.

Aspect 29. The system of any of Aspects 17 through 28, wherein theportion of the neck tube disposed within the stem is distanced from thesidewall of the stem by a distance that is greater than or equal to 0.70mm.

Aspect 30. A system comprising:

a controller that is operatively configured to send and receiveelectronic signals; and

an ultrasonic probe comprising a fitting assembly, a barrel extendingdownwardly from the fitting assembly, and a plurality of ultrasonicsensors located within the barrel, each of the plurality of ultrasonicsensors being adapted to receive electronic signals sent from thecontroller, emit sound waves in response to the electronic signals sentfrom the controller, detect sound waves, and transmit electronic signalsto the controller indicative of the detected sound waves;

wherein the controller is programmed to send electronic signals to onlyone of the plurality of ultrasonic sensors at a time.

Aspect 31. The system of Aspect 30, wherein the controller is programmedto send an electronic signal to a first ultrasonic sensor of theplurality of ultrasonic sensors and receive an electronic signal fromthe first ultrasonic sensor of the plurality of ultrasonic sensors priorto sending an electronic signal to any other ultrasonic sensor of theplurality of ultrasonic sensors.

Aspect 32. The system of Aspects 30 or 31, wherein the plurality ofultrasonic sensors includes at least 5 ultrasonic sensors.

Aspect 33. The system of Aspects 30 or 31, wherein the plurality ofultrasonic sensors includes at least 12 ultrasonic sensors.

Aspect 34. The system of any of Aspects 30 through 33, wherein eachultrasonic sensor of the plurality of ultrasonic sensors is electricallycoupled to the controller by at least one unshielded wire.

Aspect 35. The system of any of Aspects 30 through 34, furthercomprising a multi conductor shielded cable, wherein all ultrasonicsensors of the plurality of ultrasonic sensors are electrically coupledto the controller by the multi conductor shielded cable.

Aspect 36. A method of operating a probe having a plurality ofultrasonic sensors, the method comprising:

(a) sending an electronic signal to one of the plurality of ultrasonicsensors;

(b) receiving an electronic signal from the ultrasonic sensor of step(a);

(c) sending an electronic signal to another one of the of the pluralityof ultrasonic sensors only after step (b) has been performed; and

(d) receiving an electronic signal from the ultrasonic sensor of step(c).

Aspect 37. The method of Aspect 36, further comprising the step of:

(e) repeating steps (a) through (d) so that steps (a) and (b) or steps(c) and (d) have been performed a first time for each ultrasonic sensorof the plurality of ultrasonic sensors.

Aspect 38. The method of Aspect 37, further comprising the step of:

(f) repeating steps (a) through (d) so that steps (a) and (b) or steps(c) and (d) have been performed a second time for each ultrasonic sensorof the plurality of ultrasonic sensors, wherein step (f) is performedonly after step (e) has been performed.

Aspect 39. The method of any of Aspects 36 through 38, whereinelectronic signals are sent to the plurality of ultrasonic sensors usinga plurality of inner conductors of a multi conductor shielded cable, andwherein electronic signals are received from the plurality of ultrasonicsensors using an outer shield of the multi conductor shielded cable.

Aspect 40. A method of assembling a probe comprising a neck tube, acollar, an inner tube, an outer tube, and a plurality of ultrasonicsensors, the method comprising:

(a) coupling the inner tube to the collar;

(b) coupling the collar to the neck tube;

(c) coupling the plurality of ultrasonic sensors to a sidewall of theinner tube; and

(d) only after performing steps (a) through (c), coupling the outer tubeto the collar, thereby creating an internal volume between the innertube and the outer tube that encloses the plurality of ultrasonicsensors.

Aspect 41. The method of Aspect 40, further comprising:

(e) prior to coupling the outer tube to the collar, providing electricalcurrent to one or more ultrasonic sensors of the plurality of ultrasonicsensors via one or more wires extending from each of the plurality ofultrasonic sensors, through the internal volume, through the collar, andthrough the neck tube.

Aspect 42. The method of Aspects 40 or 41, wherein an upper opening ofthe inner tube is welded to a side opening of the collar, an upperopening of the collar is welded to a lower opening of the neck tube, anda lower opening of the collar is welded to an upper opening of the outertube.

Aspect 43. The method of any of Aspects 40 through 42, wherein couplingthe outer tube to the collar comprises welding the outer tube to thecollar.

Aspect 44. The method of any of Aspects 40 through 43, furthercomprising:

(e) prior to coupling the outer tube to the collar, connecting allultrasonic sensors of the plurality of ultrasonic sensors to acontroller by a single multi conductor shielded cable.

Aspect 45. The method of any of Aspects 40 through 44, furthercomprising:

(e) prior to coupling the outer tube to the collar, connecting aseparate signal line that is not individually shielded to eachultrasonic sensor of the plurality of ultrasonic sensors, and connectingeach ultrasonic sensor of the plurality of ultrasonic sensors to acommon return line.

Aspect 46. The method of Aspect 45, wherein each separate signal line isan internal conductor of a multi conductor shielded cable.

Aspect 47. The method of Aspect 46, wherein the common return line is anouter shield of the multi conductor shielded cable.

Aspect 48. A method of assembling a probe, the method comprising:

(a) providing a probe barrel assembly comprising an inner tube;

(b) coupling a neck tube to the probe barrel assembly;

(c) installing a plurality of ultrasonic sensors into the probe barrelassembly; and

(d) coupling an outer tube to the probe barrel assembly, wherein step(d) is performed only after steps (a) through (c) have been performed.

Aspect 49. The method of Aspect 48, wherein the probe barrel assemblyfurther comprises a collar welded to the inner tube.

Aspect 50. The method of Aspect 49, wherein coupling the outer tube tothe probe barrel assembly comprises welding the outer tube to thecollar.

Aspect 51. The method of any of Aspects 48 through 50, furthercomprising:

(e) prior to coupling the outer tube to the probe barrel assembly,providing electrical current to one or more ultrasonic sensors of theplurality of ultrasonic sensors via one or more wires extending fromeach of the plurality of ultrasonic sensors.

Aspect 52. The method of any of Aspects 48 through 51, wherein step (c)comprises:

coupling the plurality of ultrasonic sensors to a sidewall of the innertube; and

connecting all ultrasonic sensors of the plurality of ultrasonic sensorsto a controller by a multi conductor shielded cable.

Aspect 53. The method of any of Aspects 48 through 51, wherein step (c)comprises:

coupling the plurality of ultrasonic sensors to a sidewall of the innertube;

connecting a separate signal line that is not individually shielded toeach ultrasonic sensor of the plurality of ultrasonic sensors; and

connecting each ultrasonic sensor of the plurality of ultrasonic sensorsto a common return line.

Aspect 54. The method of Aspect 53, wherein each separate signal line isan internal conductor of a multi conductor shielded cable.

Aspect 55. The method of Aspect 54, wherein the common return line is anouter shield of the multi conductor shielded cable.

Aspect 56. An ultrasonic probe comprising:

a plurality of ultrasonic sensors disposed within an internal volume ofthe ultrasonic probe, wherein each ultrasonic sensor of the plurality ofultrasonic sensors is connected to a separate signal line that is notindividually shielded.

Aspect 57. The ultrasonic probe of Aspect 56, wherein each ultrasonicsensor of the plurality of ultrasonic sensors is further connected to acommon return line.

Aspect 58. The ultrasonic probe of Aspect 57, wherein the signal lineconnected to each ultrasonic sensor is an internal conductor of acoaxial cable and the common return line is an outer shield of thecoaxial cable.

Aspect 59. The ultrasonic probe of Aspect 56, further comprising acoaxial cable, wherein all ultrasonic sensors of the plurality ofultrasonic sensors are connected to the coaxial cable.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction withthe appended drawing figures wherein like numerals denote like elements.

FIG. 1A is an exploded perspective view of an ultrasonic probe inaccordance with an exemplary embodiment of the present invention;

FIG. 1B is a non-exploded sectional view, taken along line 1B-1B, of theultrasonic probe of FIG. 1A;

FIG. 2A is a perspective view of the ultrasonic probe of FIGS. 1A and 1Binstalled on a container in accordance with an exemplary embodiment ofthe present invention;

FIG. 2B is an enlarged, partial sectional view, taken along line 2B-2B,of portions of the ultrasonic probe and container shown within thedashed-line area of FIG. 2A;

FIG. 3A is an exploded perspective view of an ultrasonic probe inaccordance with another exemplary embodiment of the present invention;and

FIG. 3B is a non-exploded sectional view, taken along line 3B-3B, of theultrasonic probe of FIG. 3A.

FIG. 4A is an exploded perspective view of certain components of theultrasonic probe of FIGS. 3A and 3B.

FIG. 4B is a non-exploded perspective view of the components of theultrasonic probe shown in FIG. 4A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The ensuing detailed description provides preferred exemplaryembodiments only, and is not intended to limit the scope, applicability,or configuration of the invention. Rather, the ensuing detaileddescription of the preferred exemplary embodiments will provide thoseskilled in the art with an enabling description for implementing thepreferred exemplary embodiments of the invention. Various changes may bemade in the function and arrangement of elements without departing fromthe spirit and scope of the invention, as set forth in the appendedclaims.

In the figures, elements that are similar to those of other embodimentsof the present invention are represented by reference numerals increasedby a value of 100. Such elements should be regarded as having the samefunction and features unless otherwise stated or depicted herein, andthe discussion of such elements may therefore not be repeated formultiple embodiments.

The term “conduit,” as used in the specification and claims, refers toone or more structures through which fluids can be transported betweentwo or more components of a system. For example, conduits can includepipes, ducts, passageways, and combinations thereof that transportliquids, vapors, and/or gases.

The term “flow communication,” as used in the specification and claims,refers to the nature of connectivity between two or more components thatenables liquids, vapors, and/or gases to be transported between thecomponents in a controlled fashion (i.e., without leakage). Coupling twoor more components such that they are in flow communication with eachother can involve any suitable method known in the art, such as with theuse of welds, flanged conduits, gaskets, and bolts. Two or morecomponents may also be coupled together via other components of thesystem that may separate them.

In order to aid in describing the invention, directional terms may beused in the specification and claims to describe portions of the presentinvention (e.g., upper, lower, left, right, etc.). These directionalterms are merely intended to assist in describing and claiming theinvention, and are not intended to limit the invention in any way. Inaddition, reference numerals that are introduced in the specification inassociation with a drawing figure may be repeated in one or moresubsequent figures without additional description in the specificationin order to provide context for other features.

FIGS. 1A and 1B show an ultrasonic probe 100 in accordance with anexemplary embodiment of the present invention. More specifically, FIG.1A shows an exploded perspective view of the ultrasonic probe 100 andFIG. 1B shows a non-exploded sectional view of the ultrasonic probe 100taken along line 1B-1B of FIG. 1A.

The ultrasonic probe 100 comprises seal fitting members 102 a and 102 b,a flexible connector 104, a cable sheath 106, a neck tube 108 having ashoulder portion 113, and a barrel 123. As discussed in greater detailherein, the seal fitting members 102 a and 102 b are portions of a sealfitting assembly 157 (see also FIG. 2B) that secures the ultrasonicprobe 100 to a container 159. In this exemplary embodiment, the sealfitting assembly 157 is a face seal fitting assembly, where the sealfitting member 102 a is a face seal fitting gland having a through hole103 and the seal fitting member 102 b is a standard sized face sealfitting having a three-quarter-inch (19.1 mm) hex nut. In thisembodiment, the seal fitting member 102 b rests on a lip 149 of the sealfitting member 102 a and can be rotated relative to the seal fittingmember 102 a about an axis drawn through the through hole 103. Inalternative embodiments, as will be apparent to those of ordinary skillin the art, the seal fitting members 102 a and 102 b can have otherdimensions and features, such as a longer gland, a half-inch (12.7 mm)or a non-standard size face seal fitting, and/or a seal fitting member102 b that is bonded to the seal fitting member 102 a. Similarly, othertypes of fittings can be used for seal fitting assembly 157, such as,for example, a surface mount C-seal.

The seal fitting member 102 a is coupled to the flexible connector 104and the cable sheath 106. The neck tube 108 comprises an upper end 110that defines an upper opening, a lower end 112 that defines a loweropening, and a sidewall 114. In this embodiment, the shoulder portion113 of the neck tube 108 comprises a shoulder tube 116 having an upperend 118 that defines an upper opening and a lower end 120 that defines alower opening. The shoulder tube 116 is conical in shape and provides asmooth transition from the neck tube 108 to the outer tube 122 of thebarrel 123. The lower end 112 of the neck tube 108 is disposed withinthe shoulder tube 116 and the shoulder tube 116 is coupled to thesidewall 114 of the neck tube 108. In other embodiments, the entire necktube 108, including the shoulder portion 113, can be formed of a singleunitary part. The upper end 110 of the neck tube 108 is disposed withinthe through hole 103 of the seal fitting member 102 a and within theflexible connector 104.

The barrel 123 comprises an outer tube 122, an inner tube 132, and adisc cap 140. The outer tube 122 has an upper end 124 that defines anupper opening, a lower end 126 that defines a lower opening, a sidewall128, and a through hole 130 disposed in the sidewall 128 near the upperend 124. The upper end 124 of the outer tube 122 is coupled to the lowerend 120 of the shoulder tube 116.

The inner tube 132 comprises an upper end 124 that defines an upperopening, a lower end 136 that defines a lower opening, and a sidewall138. In this exemplary embodiment, the upper end 134 defines an upperopening that is approximately perpendicular to the lower opening definedby the lower end 136. The inner tube 132 defines a conduit 144 (see FIG.1B). In should be understood that, in other embodiments of theinvention, the conduit may not be fully enclosed, as is the case withultrasonic probe 100. For example, in a probe having a “tuning fork”style barrel (i.e., having two spaced-apart members extendingdownwardly) the conduit could comprise a space located between the twospaced-apart members.

The disc cap 140 comprises an inner rim 142 that defines an opening. Inan assembled configuration, the entirety of the inner tube 132 isdisposed within the outer tube 122, the upper end 134 of the inner tube132 is aligned with the through hole 130 disposed in the sidewall 128,and the lower end 136 of the inner tube 132 is aligned with the lowerend 126 of the outer tube 122. The upper end 134 of the inner tube 132is coupled to the sidewall 128. The disc cap 140 is coupled to the lowerend 126 of the outer tube 122 and the lower end 136 of the inner tube132, thereby coupling the lower end 126 of the outer tube 122 to thelower end 136 of the inner tube 132.

The conduit 144 is disposed within the barrel 123 and has a loweropening defined by the lower end 136 of the inner tube 132 (the loweropening can also be regarded as being defined by the inner rim 142 ofthe disc cap 140) (see FIG. 1B). When the barrel 123 is inserted into acontainer (see container 159 of FIGS. 2A and 2B), the conduit 144 is inflow communication with the internal volume of the container that holdsliquid such that the liquid can flow through the conduit 144.

The sidewall 128 of the outer tube 122 and the sidewall 138 of the innertube 132 define an internal volume 146 (i.e., a compartment)therebetween that is also bounded by the disc cap 140, as shown. Theinternal volume 146 is isolated from the conduit 144 (i.e., the internalvolume 146 is not in flow communication with the conduit 144) such thatany liquid flowing through the conduit 144 cannot enter the internalvolume 146.

A plurality of ultrasonic sensors 156 is disposed within the internalvolume 146 of the barrel 123. In this exemplary embodiment, theplurality of ultrasonic sensors 156 includes twelve (12) ultrasonicsensors 156 a through 156 l that are coupled to the sidewall 138 of theinner tube 132. In this embodiment, each of the plurality of ultrasonicsensors 156 is bonded to the sidewall 138 with an epoxy. Other suitablemeans for coupling can also be used, such as double-sided tape or otheradhesives. In other embodiments, the plurality of ultrasonic sensors 156can include a greater or lesser number of sensors. Preferably theplurality of ultrasonic sensors 156 includes at least 5 ultrasonicsensors. The plurality of ultrasonic sensors 156 can be implemented withany suitable ultrasonic sensors that are known to those of ordinaryskill in the art, such as, for example, piezoelectric crystals. Eachultrasonic sensor of the plurality of ultrasonic sensors 156 is orientedto emit sound waves through the sidewall 138 and the conduit 144 (andany liquid present therein) and detect the sound waves that are echoedback. Each ultrasonic sensor of the plurality of ultrasonic sensors 156includes wiring 158 (comprising at least one wire) that extends from theinternal volume 146, through the neck tube 108, and through the cablesheath 106. The wiring 158 is terminated at a connector 107 that isplugged into a controller 109 (see FIG. 2A).

The controller 109 is a programmable data processing device thattransmits electronic signals to the plurality of ultrasonic sensors 156,receives electronic signals from the plurality of ultrasonic sensors156, and determines the level of liquid within a container into whichthe ultrasonic probe 100 is inserted. In this embodiment, the controller109 comprises one or more microprocessors (not shown), a power supply(not shown), at least one input/output port (not shown) to receive theconnector 107, and a light-emitting-diode (LED) meter 111 that providesa visual indication of the amount of liquid within the container. Inalternative embodiments, the controller 109 can include otherinput/output ports and/or other aural and visual mechanisms forindicating the level of liquid within the container. Similarly, thecontroller 109 may be implemented with any type of programmable dataprocessing device, including a personal computer executing controlsoftware.

For each ultrasonic sensor of the plurality of ultrasonic sensors 156,the controller 109 transmits an electronic signal (i.e., a pulse) to theultrasonic sensor via the wiring 158, which causes the ultrasonic sensorto emit sound waves (i.e., the piezoelectric crystal oscillates). Theultrasonic sensor then receives echoed sound waves and converts theechoed waves into an electronic signal that is transmitted back to thecontroller 109 via the wiring 158. As previously discussed, thecontroller 109 interprets the intensity of the received signal as wellas the time that elapsed between sending the electronic signal to theultrasonic sensor and receiving the electronic signal from theultrasonic sensor to determine whether there is liquid at the portion ofthe conduit 144 at which that particular sensor is disposed.Accordingly, by using the plurality of ultrasonic sensors 156, thecontroller 109 can determine the level of liquid along the length of theconduit 144 and therefore the amount of liquid within the container intowhich the barrel 123 is inserted. Each sensor of the plurality ofultrasonic sensors 156 is represented by an LED in the LED meter 111 toprovide a visual indication of the amount of liquid within the container(e.g., each LED is illuminated only when liquid is detected by aparticular sensor).

The controller 109 can be programmed to transmit signals to, and receivesignals from, less than all of the ultrasonic sensors 156 a through 156l of the plurality of ultrasonic sensors 156 at the same time. Thisfeature eliminates the need for the wiring 158 for the plurality ofultrasonic sensors 156 to be individually shielded and also allows theultrasonic sensors 156 a through 156 l to be disposed closer together.In prior art systems, the wiring that connects the ultrasonic sensors toa controller is typically individually shielded to protect againstinterference (i.e., crosstalk) that results from electronic signalsbeing transmitted to and from all of the ultrasonic sensors in the probeat the same time. For example, the wiring for each ultrasonic sensor ina typical prior art design may include a coaxial cable in which theinner conductor serves as the signal line to the ultrasonic sensor andthe outer shield serves as the ground (e.g., grounded to a steel tube ofthe probe) and the signal return from the ultrasonic sensor. In priorart systems, the ultrasonic sensors within the probe must also be spacedfather apart to avoid interference that results from the ultrasonicsensors simultaneously emitting sound waves. Each of thesecharacteristics (i.e., added bulk from multiple shielded cables andgreater spacing between sensors) limits the number of ultrasonic sensorsthat can be disposed in a probe without increasing the size of the probeand related hardware.

In a preferred embodiment, the controller 109 is programmed or otherwiseoperatively configured to transmit signals to, and receive signals from,one ultrasonic sensor of the plurality of ultrasonic sensors 156 at atime. For example, the controller 109 can be programmed to firsttransmit an electronic signal to the ultrasonic sensor 156 a and awaitreceipt of the return signal from the ultrasonic sensor 156 a, thentransmit an electronic signal to the ultrasonic sensor 156 b and awaitreceipt of the return signal from the ultrasonic sensor 156 b, and so onfor each ultrasonic sensor of the plurality of ultrasonic sensors 156.Upon having transmitted an electronic signal to, and received anelectronic signal from, each of the plurality of ultrasonic sensors 156a first time (in this embodiment, beginning with ultrasonic sensor 156 aand ending with ultrasonic sensor 156 l), the controller 109 repeats thesequence and transmits an electronic signal to, and receives anelectronic signal from, the ultrasonic sensor 156 a and each of theplurality of ultrasonic sensors 156 a second time, and so on for as longas the ultrasonic probe 100 is being operated. In this manner, thepotential for interference between the wiring 158 for each ultrasonicsensor 156 a through 156 l and between the ultrasonic sensors themselvesis greatly reduced or eliminated because the ultrasonic sensors 156 athrough 156 l are not all simultaneously emitting or receiving soundwaves and the wiring 158 for each of the ultrasonic sensors 156 athrough 156 l is not simultaneously carrying electronic signals.

This method of operating the plurality of ultrasonic sensors 156eliminates the need for the wiring 158 for each ultrasonic sensor 156 athrough 156 l to be individually shielded and the ultrasonic sensors 156a through 156 l can be disposed closer together (i.e., even closer thanis shown in FIG. 1B), both of which enable a greater number ofultrasonic sensors to be disposed within the barrel 123. In an exemplaryconfiguration, the wiring 158 comprises a multi conductor shielded cablehaving a plurality of inner conductors that are not individuallyshielded, where a separate inner conductor is connected to eachultrasonic sensor of the plurality of ultrasonic sensors 156 to serve asthe signal line, and an outer shield of the multi conductor shieldedcable serves as a common return line and ground for all of theultrasonic sensors of the plurality of ultrasonic sensors 156. Forexample, a coaxial cable can be used as the multi conductor shieldedcable, where the inner conductors are connected to the plurality ofultrasonic sensors 156 to serve as the signal lines, and the outershield of the coaxial cable serves as the common return line.

The neck tube 108 is disposed within the seal fitting members 102 a and102 b and the flexible connector 104. The neck tube 108 is secured tothe seal fitting member 102 a by a fusion weld (i.e., a bead) madewithin the weld zone 148. Preferably, the weld occupies only a portionof the weld zone 148 and is made where the sidewall 114 of the neck tube108 abuts the seal fitting member 102 a. The seal fitting member 102 aincludes a protruding sealing surface (i.e., a seal face) 150 thatextends around the neck tube 108. The protruding sealing surface 150 hasan inner edge 151 that is separated from the sidewall 114 of the necktube 108 by a distance D1. In order to prevent impairment of theprotruding sealing surface 150 by a weld within the weld zone 148 (e.g.,welding material can create a raised surface and/or the heat of weldingcan deform the protruding sealing surface 150), distance D1 ispreferably at least 2.0 mm and, more preferably, at least 6.0 mm. Theseal fitting member 102 b includes a threaded region 152 that engages anopposite threaded region 166 of another seal fitting member 164 (seeFIG. 2B) of the seal fitting assembly 157, as discussed later in thisspecification. Testing ports 154 a and 154 b are used for leak detectionwhen the ultrasonic probe 100 is secured to the container 159, asdiscussed in greater detail with regard to FIG. 2B.

The barrel 123 has an outer diameter D3 (i.e., the outer diameter of theouter tube 122). The neck tube 108 and the inner tube 132 have an outerdiameter D2 that is less than the outer diameter D3 of the barrel 123.The larger outer diameter D3 of the barrel 123 relative to the outerdiameter D2 of the inner tube 132 provides an increased amount of spacewithin the internal volume 146 that is necessary to house the increasednumber of ultrasonic sensors 156 a through 156 l and their respectivewiring 158. Preferably, the ratio of the outer diameter D2 of the innertube 132 to the outer diameter D3 of the barrel 123 is less than orequal to 0.95. More preferably, the ratio of the outer diameter D2 ofthe inner tube 132 to the outer diameter D3 of the barrel 123 is lessthan or equal to 0.95 and greater than or equal to 0.3. More preferably,the ratio of the outer diameter D2 of the inner tube 132 to the outerdiameter D3 of the barrel 123 is less than or equal to 0.8, and theouter diameter D3 of the barrel 123 is no greater than 0.827 inches(21.0 mm). More preferably, the ratio of the outer diameter D2 of theinner tube 132 to the outer diameter D3 of the barrel 123 is less thanor equal to 0.8 and greater than or equal to 0.4. More preferably, theouter diameter D2 of the inner tube 132 is approximately five-sixteenthsof an inch (7.9 mm), and the outer diameter D3 of the barrel 123 isapproximately five-eighths of an inch (15.9 mm). Preferably, thereexists a minimum distance between the sidewall 128 of the outer tube 122and the sidewall 138 of the inner tube 132 of at least 0.10 inches (2.5mm) where the plurality of ultrasonic sensors 156 includes fourultrasonic sensors, and a minimum distance of at least 0.15 inches (3.8mm) where the plurality of ultrasonic sensors 156 includes the twelve(12) ultrasonic sensors 156 a through 156 l.

FIG. 2A shows a perspective view of the ultrasonic probe 100 installedon a container 159 in accordance with an exemplary embodiment of thepresent invention. The ultrasonic probe 100 includes the controller 109and the LED meter 111, as previously discussed. The container 159comprises a body 160, an upper portion 162, and a seal fitting member164 coupled to the upper portion 162. As will be apparent to those ofordinary skill in the art, the container 159 may include othercomponents that are not shown in FIGS. 2A and 2B for clarity andillustrative purposes (e.g., additional valves and hardware forrefilling the container 159). The body 160 and upper portion 162 definean internal volume that can contain fluid. In this embodiment, the upperportion 162 is a lid coupled to the body 160. In other embodiments, theupper portion 162 can be an integral part of the body 160. The sealfitting member 164, like the seal fitting members 102 a and 102 b, is aportion of the seal fitting assembly 157 that secures the ultrasonicprobe 100 to the container 159. In this exemplary embodiment, thecomponents of the container 159 are composed of one or more metals.

FIG. 2B shows a cross sectional view of the portion the ultrasonic probe100 and container 159 within the dashed box of FIG. 2A, taken along theline 2B-2B. As shown, a stem 168 is disposed in a hole in the upperportion 162 of the body 160 of the container 159. In this embodiment,the stem 168 is a face seal fitting gland that is bonded (e.g., welded)to the upper portion 162 of the body 160. The stem 168 comprises aprotruding sealing surface 170, a lip 172, and a sidewall 174. Thesidewall 174 of the stem 168 has an inner diameter D4 that is greaterthan the outer diameter D3 of the barrel 123 such that the barrel 123can be inserted into the stem 168. The seal fitting member 164 isdisposed around the stem 168 and comprises a threaded region 166 thatengages the threaded region 152 of the seal fitting member 102 b (i.e.,the threaded regions 152 and 166 have complimentary threading such asfemale and male threading, respectively). A metal gasket 176 having athrough hole is disposed between the protruding sealing surface 150 ofthe seal fitting member 102 a and the protruding sealing surface 170 ofthe stem 168.

In a fully installed configuration, the barrel 123 is inserted throughthe metal gasket 176 and the stem 168 such that the barrel is disposedinside of the container 159 and the neck tube is disposed within thestem 168 and the metal gasket 176. The threaded region 152 of the sealfitting member 102 b is then threaded onto the threaded region 166 ofthe seal fitting member 164 such that the seal fitting member 102 bengages (i.e., presses against) the lip 149 of the seal fitting member102 a, the seal fitting member 164 engages the lip 172 of the stem 168,and the metal gasket 176 is compressed between the protruding sealingsurface 150 of the seal fitting member 102 a and the protruding sealingsurface 170 of the stem 168. In this manner, the protruding sealingsurface 170, the protruding sealing surface 150, and the metal gasket176 form a metal-on-metal seal that prevents fluid (i.e., liquid, vapor,and/or gas) from escaping or entering the container 159.

In the fully installed configuration, in this exemplary embodiment, adistance S1 exists between the sidewall 114 of the neck tube 108 and thesidewall 174 of the stem 168; a distance S2 exists between the upperportion 162 (i.e., lid) of the container 159 and the upper end 118 ofthe shoulder tube 116, and the upper end 118 of the shoulder tube 116 islocated below the lower-most portion of the stem 168; and a distance S3exists between the upper portion 162 of the container 159 and the upperend 124 of the outer tube 122 of the barrel 123. Preferably, thedistance S2 is greater than or equal to 0.10 inches (2.5 mm) and thedistance S1 is greater than or equal to 0.70 mm. Generally, thedistances S1, S2 and S3 are preferably large enough to allow fluid totravel in between the sidewall 114 of the neck tube 108 and the sidewall174 of the stem 168, but also drain back down and return into thecontainer 159 under the force of gravity. Stated differently, thedistances S1, S2 and S3 are preferably large enough to avoid capillaryaction in which fluid is retained between the sidewall 114 of the necktube 108 and the sidewall 174 of the stem 168. Avoiding such capillaryaction helps maximize the usable quantity of chemical reagent that canbe drawn out of the container 159 for use, and also ensures that duringcleaning of the container 159 and the ultrasonic probe 100 in the fullyinstalled configuration, no residual chemicals are left behind topotentially contaminate fresh chemical reagent that is later added tothe container 159.

The ultrasonic probe 100 satisfies a need in the art for an ultrasonicprobe having increased quantities of ultrasonic sensors that can be usedwith existing container fittings having standardized dimensions. Thebarrel 123 has an outer diameter D3 that provides an increased amount ofspace within the internal volume 146 that is necessary to house theincreased number of ultrasonic sensors 156 a through 156 l and theirrespective wiring 158. In prior art ultrasonic probe designs, the barreltypically extends into the seal fitting assembly. An increased outerdiameter of the barrel would therefore require a larger and/ornon-standard seal fitting assembly, or modifying a standard seal fittingassembly such as by boring out a through hole (e.g., through hole 103 ofthe seal fitting member 102 a) so it can receive the larger barreldiameter. However, non-standard fitting assemblies are typically muchmore expensive than their standardized counterparts and may also requirethe use of other non-standardized components. Non-standard fittingassemblies also do not benefit from the extensive testing and provenhistory of standardized fitting assemblies for use in semiconductormanufacturing processes. Larger seal fittings also require more space onthe lid of the container (e.g., upper portion 162) and can makeobtaining a tight seal more difficult. Finally, the inventors have foundthat attempts to modify standard seal fitting assemblies to receive alarger barrel diameter can negatively affect the structural integrity ofthe ultrasonic probe and/or the seal fitting assembly. For example,referring to FIG. 1B, if the through hole 103 in the seal fitting member102 a was bored out to receive the larger outer diameter D2 instead ofthe outer diameter D2 of the neck tube 108, the distance D1 would bedecreased. As a result, the size of the weld zone 148 would also bedecreased, and the heat of welding could damage (i.e., warp) theprotruding sealing surface 150 and negatively affect the integrity ofthe seal made between the protruding sealing surface 150 and the metalgasket 176.

Unlike prior art probe designs, the barrel 123 of the ultrasonic probe100 does not extend into the seal fitting member 102 a. Instead, thebarrel 123 is coupled to the neck tube 108, which is in turn coupled tothe seal fitting member 102 a. The stem 168 is bored out such that theinner diameter D4 of the stem 168 is greater than the outer diameter D3of the barrel 123 and the barrel 123 can be inserted into the stem 168.The neck tube 108 has an outer diameter D2 that is less than the outerdiameter D3 of the barrel 123 (i.e., the ratio of D2 to D3 is less thanone), which enables the through hole 103 of the seal fitting members 102a to have a smaller bore size, as opposed to requiring a larger sealfitting (e.g., a 1 inch seal fitting) or boring out the through hole 103in the seal fitting member 102 a to accommodate the increased outerdiameter D3 of the barrel 123. The smaller outer diameter D2 of the necktube 108 also provides the necessary distance D1 to have a sufficientlylarge weld zone 148 such that the neck tube 108 and the seal fittingmember 102 a can be welded together without welding material and/orwelding heat impairing the protruding sealing surface 150. Preventingsuch damage to the protruding sealing surface 150 is critical tomaintaining the integrity of the seal between the protruding sealingsurface 150 and the metal gasket 176, and therefore maintaining theassay (purity) of the chemical reagent for use in semiconductormanufacturing.

FIG. 3A is an exploded perspective view of an ultrasonic probe 200 inaccordance with another exemplary embodiment of the present invention.FIG. 3B is a non-exploded sectional view of the ultrasonic probe 200taken along line 3B-3B. FIG. 4A is an exploded perspective view ofcertain components of the ultrasonic probe 200, and FIG. 4B is anon-exploded perspective view of the components of the ultrasonic probe200 shown in FIG. 4A.

The ultrasonic probe 200 shares many similarities with the ultrasonicprobe 100, but differs with respect to the construction of the neck tube208 and the barrel 223. In this embodiment, the shoulder portion 213 ofthe neck tube 208 is formed by the sidewall 214 (rather than a separatepiece, as is the case with shoulder tube 116 of ultrasonic probe 100)and is integral with the remainder of the neck tube 208 (i.e., the necktube 208 and shoulder portion 213 are a single piece of material). Theshoulder portion 213 has a bell shape that begins at the portion of thesidewall 214 indicated at 211 and transitions from the outer diameter D2of the neck tube 208 to the outer diameter D3 of the neck tube 208,which is also the outer diameter of the barrel 223. The lower end 212 ofthe neck tube 208 also defines a lower opening having a diameter that isgreater than the outer diameter D2 of the neck tube 208.

In this embodiment, the barrel 223 comprises a collar 215, an outer tube222, an inner tube 232, and a disc cap 240. The collar 215 comprisesupper end 217 defining an upper opening, a lower end 219 defining alower opening, a sidewall 221, and a through hole 225 disposed in thesidewall 221.

Unlike the ultrasonic probe 100, the outer tube 222 of the ultrasonicprobe 200 does not include a through hole disposed in the sidewall 228,and the upper end 224 of the outer tube 222 is not coupled to a shouldertube or to the lower end 212 of the neck tube 208. Instead, the upperend 234 of the inner tube 232 is aligned with the through hole 225disposed in the sidewall 221 of the collar 215, with the upper end 234of the inner tube 232 being coupled to the sidewall 221 of the collar215. The upper end 217 of the collar 215 is coupled to the lower end 212of the neck tube 208, and the upper end 224 of the outer tube 222 iscoupled to the lower end 219 of the collar 215. The disc cap 240 iscoupled to the lower end 226 of the outer tube 222 and the lower end 236of the inner tube 232, thereby coupling the lower end 226 of the outertube 222 to the lower end 236 of the inner tube 232.

The collar 215 enables the barrel 223 to be constructed as one or moreassemblies. This feature has been found to be advantageous because thebarrel 223 can be partially assembled and the plurality of ultrasonicsensors 256 can be tested prior to completing assembly of the barrel 223and enclosing the plurality of ultrasonic sensors 256 in the internalvolume 246. In addition, this feature is advantageous because most ofthe components of the barrel 223 can be welded together prior toinstalling the plurality of ultrasonic sensors 256, where the heat fromwelding might otherwise damage the plurality of ultrasonic sensors 256and/or the bonds which hold the plurality of ultrasonic sensors 256 inplace within the internal volume 246.

In a preferred embodiment, for example, an assembly is first constructedcomprising the collar 215, the inner tube 232, and the disc cap 240 bywelding the upper end 234 of the inner tube 232 to the collar 215 andwelding the lower end 236 of the inner tube 232 to the disc cap 240. Theassembly is then coupled to the neck tube 208 by welding the upper end217 of the collar 215 to the lower end 212 of the neck tube 208. Theplurality of ultrasonic sensors 256 are then installed into the assemblyby coupling the plurality of ultrasonic sensors 256 to the sidewall 238(see FIG. 3B) via epoxy or other known means of attachment. The wiring258 (comprising at least one wire) that is coupled to each ultrasonicsensor of the plurality of ultrasonic sensors 256 is extended along thesidewall 238, through the collar 215, and through the shoulder portion213 and remainder of the neck tube 208. The wiring 258 that is coupledto each ultrasonic sensor, like the wiring 158 of the ultrasonic probe100, does not need to be individually shielded, and the wiring 258 canbe implemented with a multi conductor shielded cable having separateinner conductors for each ultrasonic sensor and an outer shield thatserves as a common return line and ground for all of the ultrasonicsensors of the plurality of ultrasonic sensors 256. At this point, theplurality of ultrasonic sensors 256 can be tested (e.g., by connectingthem to a controller and providing electrical current), adjusted, and/orreplaced while they are still easily accessible. Further, any weldswhose heat might damage the ultrasonic sensors 256 and/or their bonds tothe sidewall 238 have already been performed prior to installing theplurality of ultrasonic sensors 256.

Assembly of the barrel 223 can then be completed by coupling the outertube 222 to the assembly. In this example, the outer tube 222 slidesover the disc cap 240 and over the inner tube 232 until the upper end224 of the outer tube 222 abuts the lower end 219 of the collar 215. Thecollar 215 is coupled to the neck tube 208 via a weld along acircumferential weld line 223 a (see FIG. 4B) and to the outer tube 222via a weld along a circumferential weld line 223 b, thereby enclosingthe plurality of ultrasonic sensors 256 in the internal volume 246defined between the sidewall 228 of the outer tube 222 and the sidewall238 of the inner tube 232. The inventors have found that when weldingalong the circumferential weld lines 223 a and 223 b from the outside ofthe barrel 223, any heat generated within the internal volume 246 is notgreat enough to damage the plurality of ultrasonic sensors 256 and/orthe bonds which hold the plurality of ultrasonic sensors 256 in placewithin the internal volume 246.

The ultrasonic probe 200 can be used in conjunction with the sealfitting assembly 157 to install the ultrasonic probe 200 on thecontainer 159 in the manner previously discussed with regard to theultrasonic probe 100. However, when the ultrasonic probe 200 is fullyinstalled on the container 159, the equivalent distance S2 is measuredbetween the upper portion 162 of the container 159 and the portion ofthe sidewall 214 indicated at 211 (i.e., the uppermost portion of theshoulder portion 213) rather than the upper end 118 of the shoulder tube116, and the equivalent distance S3 is measured between the upperportion 162 of the container 159 and the upper end 217 of the collar 215rather than the upper end of the outer tube 122.

While the principles of the invention have been described above inconnection with preferred embodiments, it is to be clearly understoodthat this description is made only by way of example and not as alimitation of the scope of the invention.

1-29. (canceled)
 30. A system comprising: a controller that isoperatively configured to send and receive electronic signals; and anultrasonic probe comprising a fitting assembly, a barrel extendingdownwardly from the fitting assembly, and a plurality of ultrasonicsensors located within the barrel, each of the plurality of ultrasonicsensors being adapted to receive electronic signals sent from thecontroller, emit sound waves in response to the electronic signals sentfrom the controller, detect sound waves, and transmit electronic signalsto the controller indicative of the detected sound waves; and a multiconductor shielded cable, wherein all ultrasonic sensors of theplurality of ultrasonic sensors are electrically coupled to thecontroller by the multi conductor shielded cable; wherein the controlleris programmed to send electronic signals to only one of the plurality ofultrasonic sensors at a time.
 31. The system of claim 30, wherein thecontroller is programmed to send an electronic signal to a firstultrasonic sensor of the plurality of ultrasonic sensors and receive anelectronic signal from the first ultrasonic sensor of the plurality ofultrasonic sensors prior to sending an electronic signal to any otherultrasonic sensor of the plurality of ultrasonic sensors.
 32. The systemof claim 30, wherein the plurality of ultrasonic sensors includes atleast 5 ultrasonic sensors.
 33. The system of claim 30, wherein theplurality of ultrasonic sensors includes at least 12 ultrasonic sensors.34. (canceled)
 35. (canceled)
 36. A method of operating a probe having aplurality of ultrasonic sensors, the method comprising: (a) sending anelectronic signal to one of the plurality of ultrasonic sensors usingone conductor of a plurality of inner conductors of a multi conductorshielded cable; (b) receiving an electronic signal from the ultrasonicsensor of step (a) using an outer shield of the multi conductor shieldedcable; (c) sending an electronic signal to another one of the of theplurality of ultrasonic sensors only after step (b) has been performed;and (d) receiving an electronic signal from the ultrasonic sensor ofstep (c).
 37. The method of claim 36, further comprising the step of:(e) repeating steps (a) through (d) so that steps (a) and (b) or steps(c) and (d) have been performed a first time for each ultrasonic sensorof the plurality of ultrasonic sensors.
 38. The method of claim 37,further comprising the step of: (f) repeating steps (a) through (d) sothat steps (a) and (b) or steps (c) and (d) have been performed a secondtime for each ultrasonic sensor of the plurality of ultrasonic sensors,wherein step (f) is performed only after step (e) has been performed.39-55. (canceled)
 56. An ultrasonic probe comprising: a plurality ofultrasonic sensors disposed within an internal volume of the ultrasonicprobe, wherein each ultrasonic sensor of the plurality of ultrasonicsensors is connected to a separate signal line that is not individuallyshielded and each ultrasonic sensor of the plurality of ultrasonicsensors being connected to a common return line, each signal linecomprising an internal conductor of a coaxial cable and the commonreturn line comprising an outer shield of the coaxial cable. 57.(canceled)
 58. (canceled)
 59. The ultrasonic probe of claim of claim 56,wherein all ultrasonic sensors of the plurality of ultrasonic sensorsare connected to the coaxial cable.
 60. The system of claim 30 whereinthe multi-conductor shielded cable consists of a plurality ofindividually insulated conductors that are not shielded from each other,a shield that surrounds the plurality of individually insulatedconductors, and a layer of insulation that surrounds the shield.
 61. Theultrasonic probe of claim 56 wherein the multi-conductor shielded cableconsists of a plurality of individually insulated conductors that arenot shielded from each other, a shield that surrounds the plurality ofindividually insulated conductors, and a layer of insulation thatsurrounds the shield.